The invention relates to a device for manufacturing book-binding covers.
Devices of this type are known as xe2x80x9cbook-covering machines with a horizontal processing principlexe2x80x9d [Liebau; Heinze, Industrielle Buchbinderei (Industrial Bookbinding), publ. Beruf+Schule, Itzehoe 1997, chap. 5.5.2; pp: 399 ff.], in which reference copies which are fed in via a copy cylinder and glued on an applying roll are joined, by rolling-on in a continuous running-through operation, to cover boards and back inserts which are fed in a linear manner. The book covers are then passed over, with the reference-copy edges still protruding, to a tucking-in device which folds the protruding edges round the board edges and onto the inner sides of the boards and presses them on, in successive, separate work stations for tucking in the head/foot and tucking in the sides. Finally, the book covers are pressed on with the aid of press rolls belonging to a pressing-on station and are guided in stacks out of the book-covering machine in a feeding-out device, at which point they are stored on a roller table until they are taken off manually.
Under these circumstances, the cover boards and back insert and also the joined-together book covers are moved through the machine essentially in a rectilinear material flow and, in the known book-covering machines, the plane of the said material flow is disposed parallel to the horizontal surface on which the machine stands. The finished book covers are deposited on top of one another in stacks in the feeding-out device, through the fact that partial stacks are formed in an intermediate plane, which are set down in the feeding-out plane to form a book-cover stack up to 100 mm in height. Because of this, the feeding-out level of the book-cover stacks lies about 150 mm lower than the material-flow plane of the book covers. The cover boards are decollated from a board magazine holding a stack of cover boards, and are advanced by the rear edge to the joining point. For reasons of efficiency, there is associated with the board magazine a prestacking band which stockpiles a fairly large number of cover boards, either as a stack or in imbricated formation, and feeds them successively to the board magazine. The board magazine has an approximate stacking height of 80 mm, as a result of which the level of the prestacking band lies higher than the material-flow plane of the boards by that extent.
Tucking-in systems are known in which book covers are brought downwards, when the protruding reference-copy edges are tucked in, in layers which are offset in a parallel manner, only to thereupon be transported onwards in a horizontal direction. The extent of this vertical offset may amount to 100 mm or more. With the aid of the abovementioned roller table, the book-cover stacks are guided, in the simplest manner, to any desired take-off point outside the machine, and after that it is possible to store a number of book-cover stacks until they are taken off. The force of gravity of the book-cover stack on an inclined plane is used for conveying purposes, it being necessary to make provision for a difference in height of about 80 to 120 mm for a roller table 3 to 4 m long.
Even considered on their own, the board magazine and the feeding-out device result in a difference in height of about 230 mm, by which the finished book covers are fed out lower than the cover boards are laid on. This difference in height leads to the fact that, with the laying-on of the cover boards at an ergonomic height, the taking-off of the finished book covers takes place at too low a level, if no further devices are provided in this respect. Conversely, the laying-on of the cover boards takes place at too high a level if the taking-off of the book covers is carried out at an ergonomic height. In a book-covering machine, by far the greatest throughputs of material are achieved in the laying-on of the cover boards and also in the taking-off of the book covers. Therefore, both areas of activity should be ergonomically configured as far as possible.
For a man of average size (178 cm), a height of 950 mm is proposed in [Ergonomie in Druckereien und der Papierverarbeitenden Industrie (Ergonomics in Printing Offices and the Paper-Processing Industry), Berufsgenossenschaft Druck und Papierverarbeitung (Printing and Paper-Processing Employers""Liability Insurance Association), Wiesbaden 1994, chap.: 7 Working heights; pp.; 41 ff.] as the ergonomic working height for laying on and taking off medium weights while in the standing position, whereas a height of 860 mm is recommended for a woman of average size (163 cm). A range from 900 to 1000 mm has emerged as the working height which is to be aimed at and at which both men and women are able to lay on cover boards or take off finished book covers in an ergonomic manner.
If the roller table is also taken into consideration, the difference in height already increases to more than 300 mm. Such a machine can no longer be operated ergonomically without using platforms. If use is made, in such a book-covering machine, of a tucking-in system which conveys the book covers into still lower planes, the difference in height increases to more than 400 mm. This problem can only be circumvented by the use of further devices, such as lifting tables for example.
The object of the invention consists in improving a device of the generic type for manufacturing book-binding covers, to the effect that cover boards and book covers can be laid on and taken off, respectively, at ergonomic working heights without using additional devices.
The invention achieves the object in a surprisingly simple and economic way through the fact that, in a generic device, the material flow of the boards and book covers as far as the feeding-out device is orientated in an ascending manner in relation to the horizontal surface on which the machine stands.
By means of the ascending material flow from the board magazine as far as the feeding-out device, it is possible to make up for the downwardly directed height offset, in a book-covering machine operating on the horizontal processing principle, between the prestacking band for the cover boards and the roller table for the book-cover stacks, in such a way that both the laying-on of the cover boards and the taking-off of the book-cover stacks take place at ergonomic heights. Even with an angle of ascent of 3xc2x0, an upwardly directed height offset of 157 mm is achieved in the case of a 3000 mm-long material flow extending in an ascending plane, as a result of which the downwardly directed height offset in the stacking of the book covers is more than made up for.
An angle of ascent of 8xc2x0, which is the preferred choice, results in an upwardly directed height offset of about 420 mm, if the material flow extends over an overall length of 3000 mm. This gain in height compensates for the loss in height in the board magazine (about 80 mm), in the feeding-out device (about 150 mm) and in the roller table (about 80 mm), in such a way that even a downwardly directed parallel displacement during the tucking-in of protruding reference-copy edges (about 120 mm) is virtually counteracted.
In an advantageous further development, the copy-feeding-in system is disposed below the tucking-in and pressing-on device, and the copy magazine lies in front of the feeding-out device, viewed in the direction of material flow of the boards and book covers. Because of the material flow of the book covers which ascends towards the rear, the material-flow plane of the reference covers can be raised to an extent such that an ergonomic laying-on height for the copy magazine is produced, even when the working heights for the laying-on of the cover boards and the taking-off of the book-cover stacks are designed in an ergonomic manner.